This invention relates to the oxidation of olefinic carbon-carbon double bonds to carbonyl groups. In another aspect, it relates to the oxidation of mono-olefins to a carbonyl compound, preferably a ketone. In another aspect, this invention relates to an oxidation process using a diluent system comprising at least two liquid phases with at least one being aqueous. In another aspect, it relates to the use of a two-phase diluent system with one being an aqueous phase and the other being an organic phase. In another aspect, this invention relates to a novel catalyst, namely, a palladium/copper/boric acid catalyst, for the oxidation of olefinic carbon-carbon double bonds to carbonyl groups. In yet another aspect, this invention relates to the use of a palladium/copper/boric acid catalyst in conjunction with a multiphase diluent system and a surfactant for the oxidation of olefinic carbon-carbon double bonds to carbonyl groups. In another aspect, this invention relates to a process for oxidizing internal, as well as terminal mono-olefins, to a carbonyl compound in a multi-phase system. In still another aspect, this invention relates to a low-corrosion catalyst system for the oxidation of olefinic groups to carbonyl groups. This invention also relates to a process for separating isobutylene from a mixed stream of C.sub.4 olefins. In another aspect, this invention relates to a process for producing methyl ethyl ketone in which an inexpensive C.sub.4 feed stream having a mixture of C.sub.4 olefins can be used.
The Wacker-type oxidation of ethylene to acetaldehyde using a palladium chloride/cupric chloride/hydrochloric acid catalyst in an aqueous solution has been modified and applied to the synthesis of methyl ketones from terminal olefins. However, major problems have been encountered in using the Wacker-type oxidation in the oxidation of higher olefins. One problem is that of reduced rates of reaction due to the low solubility of the olefin in the aqueous medium. Another major problem is the concomitant secondary oxidation of the ketone product which leads to poor selectivity and poor yield of desired product.
Various methods have attempted to increase the conversion and selectivity of olefins in an oxidation process, however, these methods have only been effective for the oxidation of terminal olefins and have been relatively ineffective for the oxidation of internal olefins. The use of such a system would require that only terminal olefins be used in a feed stream for the synthesis, for example, of methyl ethyl ketone from a C.sub.4 olefin, with separation of the internal olefins either before or after the reaction. If both terminal and internal olefins were able to be oxidized at a reasonable rate, however, expensive separation steps would be unnecessary and an inexpensive feed stream of a mixture of butenes, both 1- and 2-butenes, could be used to synthesize methyl ethyl ketone. Furthermore, if the catalyst system used in the oxidation process selectively oxidized only the linear olefins in a mixed stream containing linear and branched olefins, the process can be used for the simultaneous production of methyl ethyl ketone and separation of isobutylene from a stream comprising a mixture of linear butenes and isobutylene. Also, if isobutylene was not oxidized in the presence of the catalyst system, as opposed to prior art catalyst systems which oxidize isobutylene, relatively pure isobutylene can be recovered.
Corrosion of process equipment is also a problem when a catalyst containing halide ions is utilized in the oxidation process, and a low-corrosion catalyst can be desirable at times.
An object of the present invention, therefore, is to increase the conversion and selectivity of olefins in an oxidation process.
Another object is to provide an oxidation process for olefins causing little corrosion to the process equipment.
Another object is to provide for a more economical and simplified process for the manufacture of methyl ethyl ketone.
Still another object of the present invention is to provide an improved process for the purification of isobutylene when contained in a stream of linear butenes.
Yet another object is to provide an oxidation process which oxidizes internal olefins at reasonable rates.
Other objects, aspects, and the several advantages of this invention will be apparent to those skilled in the art upon a study of this disclosure and the appended claims.